The present invention relates to apparatus provided with an electric power supply control means for controlling electric power supply to a main control section.
In the field of electronic musical instruments that are a form of electronic apparatus, it has heretofore been known to turn on or off electric power supply in response to user's operation of a power supply switch, to automatically turn off the electric power supply under control of a CPU if there has been no performance event for a predetermined time period, and to turn off the electric power supply at appropriate timing within a process following operation of the power supply switch. Examples of such electronic musical instruments are disclosed in Japanese Patent Nos. 2692400 and 2847996 (hereinafter referred to as “patent literature 1” and “patent literature 2”, respectively).
Further, in the case where ON/OFF of the electric power supply is controlled not only in response to user's operation of the power supply switch but also by the CPU as disclosed in patent literature 1 and patent literature 2, it has been conventional to construct the power supply switch by use of a momentary switch, supply electric power to main equipment component parts, including the CPU, via gates in the form of transistors and relays, and control opening/closing (ON/OFF) in accordance with detection of operation of the power supply switch and control by the CPU.
However, in the case where a momentary switch is employed as the power supply switch as disclosed in patent literature 1 and patent literature 2, even when the electric power supply to the apparatus is OFF, it is necessary to keep supplying electric power to circuitry that is provided for detecting operation of the switch and controlling the gates in response to the detection of the switch operation, and thus, a certain amount of standby electric power consumption would occur. But, such standby electric power consumption is not preferable nowadays when reduction of electric power consumption are being strongly called for.
Heretofore, there has also been a demand that individual power supplies to desired ones of a plurality of apparatus connected to a multi-socket power strip be turned on or off collectively by means of a power supply switch provided on the power strip. Such a demand is strongly felt particularly in electronic musical instruments and audio equipment where a combination of apparatus to be used is frequently changed according to the situation.
For example, in cases where a plurality of keyboards are disposed and used in an overlapping arrangement and pluralities of tone generators, effecters, mixers, etc. are used placed in a rack, the numbers of the keyboards and tone generators to be powered on vary in accordance with the number of performance parts to be simultaneously played, and, in these cases, only each effecter to be used has to be powered on and each effecter not to be used may be powered off. Further, if no audio signal mixing is required, the mixers need not be powered on. Namely, a combination of apparatus to be simultaneously powered on frequently changes according to the situation. Thus, if the same operations as those having been performed till immediately before the change are to be performed again, there arises a demand to simultaneously power on the same apparatus as those having been ON till immediately before the change; because, if the same apparatus can be simultaneously powered on, the time and labor necessary for powering on the apparatus can be significantly reduced.
However, with the conventionally-known electronic musical instruments or electronic apparatus using the momentary switch, merely operating the switch of the power strip provided externally to the apparatus cannot start electric power supply or feeding to main equipment component parts, although it can stop the electric power feeding. Such a disadvantage would also be encountered in electronic apparatus other than audio signal processing apparatus.